Enable network verification on neutron deployments

Current implementation correctly verifies connectivity
of underlay network, no matter what bridge is used on
target nodes.

It does not checks ovs or bonding functionality,
which i think should be addressed by another check.

Related to blueprint network-checker-neutron-vlan

Change-Id: I78e279b26c9477739d5dacaa61b39bd3c260b87c
Merge "Enable network verification on neutron deployments"